Back pressure issue?

[Big red]

I got a 98 lifted gmc 1500 on 37s 5.7 vortec with 3.73 gears. Will always turnover when started but usually shuts off and takes a 2nd go. Runs good up to 2800 rpms and stays around 155 temperature wise. If I put the petal to the floor tho is sounds like somebody chokin and gaspin for air. Got dual pipes of the cat with no muffler was thinkin it was a back pressure problem. Just wanted to see what yall think before I go buy a muffler. Thanks

 

[JMTC]

Im no expert but I can't see the lack of back pressure causing any performance issues A larger less restrictive exaust likley better.

 

[98trck]

do you still have the cats on
the cats can be clogged , a friend bought a nice car cheap but it wouldn't run past 1800 rpm he unhooked the exhaust pipe from the exhaust manifold and it would rev he replaced the cat and now has a very nice car

 

[Big red]

Yeah the cats still on and it is clogged. Gonna take it off tommorow and see if it helps